Green manure is best fertilizer - Infonet-Biovision

Nr. 27 August 2007
Spider mites are tricky to control
Spider mites are the most important
non-insect pest of tomatos. The pest is
spreading rapidly into the drier areas
of Kenya. The eggs, which are white/
pink and tiny, are usually laid on the
under-surface of leaves. The reddish
adults (0.25 mm long) have eight legs,
and produce a fine silk webbing on
leaves which tends to protect them
from predators.
Transmission: In warm dry weather,
mites can multiply and spread very
quickly; heavy rains or irrigation can
reduce the population. They can be
dispersed by the wind – or even on
the farmers’ trousers!
Damage: Spider mites prefer the
underside of leaves, but in severe
infestations will occur on both leaf
surfaces as well as on the stems.
Heavily damaged plants are weakened,
produce smaller and lighter
fruits, or can even be killed as result
of feeding by large numbers of spider
mites.
Control: Patrol the field regularly to
determine the level of infestation.
• Cultural practices help control mites.
Keep the field clean and keep it free of
weeds. Old crops or weeds infested
with spider mites are ideal breeding
grounds for these pests – remove
them or burn them immediately after
harvest. Sticks for holding tomato
plants should be scrubbed with water
and soap before using them again.
• Natural enemies such as ladybird
beetles, lacewings or predatory mites
can control the spider mites.Therefore
avoid broad-spectrum pesticides,
especially those based on pyrethrum,
since they kill the predatory mites,
causing spider mite numbers to flare
up. You should therefore use pes-
Farmers like growing tomato varieties
which do not require stakes for
support. But these varieties are prone
to tomato blight, especially during
the wet season as they are near the
ground. The varieties pick up contaminated
water on the ground leading to
rapid infection of the tomato plant by
both early and late blight. Farmers are
advised to plant these varieties only
during the dry season when there
is less water on the ground. They
could also reduce the blight problem
by going for varieties that require
support with stakes, but care should
be taken when irrigating to ensure
Tomato plant and fruit infested by spider mite
(Photo courtesy ICIPE)
ticides (botanical or synthetic) only
when it is really necessary. If you
want to use neem, look for a product
that contains a high proportion of
neem oil, as it is more effective.
• Intercropping with garlic, basil and
onion can give some protection due to
their strong smell.
• Tomato spray: Boil moderately 1
kg of fresh tomato leaves in 2 liters
water; cool and use as a spray.
• Castor oil plant (Ricinus) spray:
Soak green seeds and leaves in water
for 24 hours, filter and spray. Caution:
Castor bean seeds are poisonous, so
do not allow people or animals to
drink the spray or eat tomatoes with
spray on them.
contaminated soil does not come into
contact with the leaves or the stem,
thus reducing the chances of spreading
the diseases.
Tomato varieties not supported by sticks are
prone to blight.
(Photo TOF)
Training: Baraka Agricultural Training
College offers a wide range of
short courses for farmers, development
workers and rural business
people: Sustainable agriculture July
29-August 4, Participatory project
planning August 5-18, Introduction to
beekeeping August 12-18, Bee equipment-making
August 19-25, ICT for
rural development September 16-23,
Processing of bee products August
14-20, Sustainable Development
October 28 – November 24, Microsaving
and Credit Scheme November
4-11, Animal health November 18-24,
Community Development November
25-December 1. Charges vary between
Ksh 6000 and Ksh 8000 covering
tuition, food accommodation and
training. Participants must apply at
least three weeks in advance to book
a place. The college also offers a 16
month Certificate in Sustainable Agriculture
and Rural Development. The
deadline for applications is August 8,
2007 for the 2007/2008 academic year.
Applicantion for a 16-month Diploma
in Sustainable Agriculture and Rural
Development course that caters for
students in East Africa will close on
August 8, 2007.
Organic Produce: David Gakere, a
Kenyan resident in Johannnesburg
is keen to contact local exporters or
farmers growing organic produce.
He would like to buy only certified
organic produce. Those with these
products can contact him.
Write to: gakere@mweb.co.za
Land for sale: 25 acres in Passenga
scheme, well-drained fertile soils on
a gentle slope, currently under potato
and oats; clean freehold title. Electricity
and piped water available. Contact
Waiyaki Mungai Tel. 0723-787171.
Amaranthus Seeds: Ronald M
Nyabuya has about 300 kg of Amaranthus
seeds. Any farmer interested in
buying them can contact him. Write to
Ronald Nyabuya P.O.Box 995, 30200,
Kitale, Tel.0721 562 678.
Charcoal Stoves: Aruba Farmers
Group are making charcoal stoves for
chicken rearing. Any farmer who is
interested can contact the group coordinator,
Mr. Kibiwot Cheruiyot, at the
following address: William Kibiwot
Cheruiyot P.O. Box 596, Kitale 30200
Tel. 0728 342 166.